Applications of chemically modified screen-printed electrodes in food analysis and quality monitoring: a review

Food analysis and food quality monitoring are vital aspects of the food industry, ensuring the safety and authenticity of various food products, from packaged goods to fast food. In this comprehensive review, we explore the applications of chemically modified Screen-Printed Electrodes (SPEs) in these critical domains. SPEs have become extremely useful devices for ensuring food safety and quality assessment because of their adaptability, affordability, and convenience of use. The Introduction opens the evaluation, that covers a wide spectrum of foods, encompassing packaged, junk food, and food quality concerns. This sets the stage for a detailed exploration of chemically modified SPEs, including their nature, types, utilization, and the advantages they offer in the context of food analysis. Subsequently, the review delves into the multitude applications of SPEs in food analysis, ranging from the detection of microorganisms such as bacteria and fungi, which are significant indicators of food spoilage and safety, to the identification of pesticide residues, food colorants, chemicals, toxins, and antibiotics. Furthermore, chemically modified SPEs have proven to be invaluable in the quantification of metal ions and vitamins in various food matrices, shedding light on nutritional content and quality.

. He received an Early Career Research Award, Core Research Grant, and an International Indo-Russia Project Grant.His research team works on biosensors, wearable electronics, biomaterials, and green synthesis of nanomaterials for biomedical applications.His h-index is 47 and the total citation of ∼7000.

Introduction
The modern world's diverse culinary landscape encompasses a wide array of foods, from meticulously craed delicacies to conveniently packaged meals, and from health-conscious, wholesome options to the irresistible allure of junk food.Food, an essential element of human existence, has evolved into a complex global industry, with products that cater to every palate, lifestyle, and dietary preference.In the midst of this remarkable diversity, the universal concern for food quality and safety resonates across all corners of the globe. 1 This concern reaches far and wide, extending beyond the boundaries of cuisine.It encapsulates the nutritional integrity of the groceries we purchase, the hygiene of the meals we consume, and the authenticity of the avours we savour.The assurance of food quality is not merely a matter of taste; it is a cornerstone of public health and well-being.In a world characterized by rapid urbanization, food globalization, and an ever-accelerating pace of life, ensuring the quality of the foods we consume is a pressing imperative. 2,3ackaged foods, emblematic of convenience and a busy lifestyle, line the shelves of supermarkets and convenience stores.These products bear the promise of enduring freshness, standardized quality, and detailed nutritional information. 4hese foods represent a captivating interplay of chemistry within the realm of modern nutrition.These products, an outcome of meticulous food processing techniques, owe their sensory allure to a web of intricate chemical reactions. 5The inclusion of various chemical additives, such as antioxidants and emulsiers, adds a layer of complexity, impacting shelf life and sensory properties. 6Ensuring the integrity of packaged foods, from the labelling to the contents within, is an ongoing pursuit.
Junk food, oen an irresistible indulgence, captures the essence of guilty pleasures.These highly processed and indulgent treats tantalize the taste buds while raising concerns about excessive sugars, fats, and articial additives. 7Monitoring the quality of junk food is essential, given its association with obesity, chronic diseases, and nutritional imbalances. 8unk foods, ubiquitous in modern diets, possess a complex chemistry.These are rich in unhealthy fats, sugars, and salts, they undergo processes like Maillard reactions and lipid oxidation.These reactions contribute to the characteristic avors, textures, and colors of these products.Nevertheless, consuming these items in excess can result in the development of advanced glycation end products (AGEs), which have been connected to long-term health problems.Understanding the chemistry of junk foods is crucial for addressing their impact on public health and nutrition.
Food quality concerns extend to the domains of foodborne pathogens, contaminants, and adulterants.Microorganisms, such as bacteria and fungi, can thrive in food products, causing spoilage or, more critically, posing health risks. 9,10Pesticide residues and chemical contaminants can nd their way into the food supply chain, necessitating rigorous monitoring.The presence of articial colorants, avor enhancers, or adulterants may compromise the authenticity and safety of various food items.Moreover, toxins and antibiotics, when present in edibles, demand swi detection to prevent health repercussions.
As the food industry navigates these complexities, innovative solutions are essential for safeguarding food quality and ensuring consumer condence.One such innovation is the utilization of Chemically Modied Screen-Printed Electrodes (SPEs) in the analysis of various food components. 11,12SPEs, characterized by their versatility, cost-effectiveness, and ease of use, have been emerged as a powerful tool for food quality assessment and safety assurance.This review explores the multifaceted applications of chemically modied SPEs in the context of food analysis, with a focus on their ability to address a spectrum of food quality issues.Through this exploration, our Fig. 1 The simple fabrication of various kinds of SPE for various applications.Three electrodes (working, counter and reference) were printed. 13imilarly, gold, platinum and graphite coated working SPEs are also can be prepared with three electrodes configurations.
goal is to provide insight into the critical role that SPEs play in contemporary food science and their potential benets which will be benecial for food safety and quality in the years to come.
The absence of literature reviews on chemically modied Screen-Printed Electrodes (SPEs) in food analysis underscores a crucial gap in understanding.As technology advances, the scope for SPEs extends into cutting-edge domains like articial intelligence (AI), blockchain, multimodal sensors, and wireless connectivity.Integrating SPEs with these latest technologies holds immense potential for revolutionizing food analysis methods.The novelty of this paper lies in its comprehensive review, exploring the uncharted territory of SPEs in conjunction with advanced technologies, providing insights not only into current applications but also shedding light on the future trends and transformative impact of chemically modied SPEs in the realm of advanced technologies.

Importance of screen-printed electrodes (SPEs)
Screen-printed electrodes (SPEs) are a fundamental component of the eld of electrochemistry, enabling precise and costeffective electrochemical measurements.These electrodes are manufactured through a versatile screen-printing process, which allows for the creation of customized electrode designs on nonconductive substrates.SPEs consist of working, counter, and reference electrodes, serving as essential tools in applications ranging from environmental monitoring to clinical diagnostics (Fig. 1). 13Their affordability and ease of mass production have made SPEs an invaluable resource for researchers and professionals, offering a practical and accessible means of studying electrochemical reactions and quantifying various analytes with precision and convenience.The standard procedures for food analysis are oen carried out in centralized laboratories, with lengthy analysis timeframes and intricate equipment.In this regard, sensors built on screen-printed electrodes (SPEs) have become more and more signicant due to their benecial attributes, like mobility and ease of use, which enable quick analysis in situations where it's needed.With an emphasis on the iden-tication of important metal toxins, pathogens, bacteria and fungi, this review offers a thorough overview of SPE-based sensors for the assessment of food safety and quality analysis.

Description and processes including types and modications of SPEs
The devices known as SPEs have become more and more popular in the last several years because of their portability, affordability, and simplicity of use.There are several types of SPEs, each designed for specic applications.SPEs are set up as an entire miniaturized electrochemical cell, usually with the working electrode (WE), the counter electrode (CE), and the reference electrode (RE). 14,15An image or pattern can be printed onto materials like paper, cloth, or polymer using the widely used screen printing technique.The process involves applying conductive ink to the surface by means of a stencil, also known as a screen.In light of this, the name of the method is screen-printed. 16Carbon-based screen-printed electrodes are prepared using screen-printing processes, carbon inks (including variables such graphite or carbon nanotubes) are usually printed on a substrate to create these electrodes. 17For the fabrication of SPEs, graphite ink, CNT ink, and Gr ink are frequently utilized. 18he most exciting advancements in electrochemical biosensors includes DNA sensors, 19 aptasensors, 20 immunosensors, 21 and enzymatic biosensors. 22Non-biological materials used in thick-lm technology include substrates like alumina, ceramics, PVC, gold, iron, etc., and the electrode's conducting pad, which is made of platinum or another metal paste or carbon ink or paste.Traditionally, the thick-lm biosensor construction employed biorecognition elements such as cells, DNA, RNA, enzymes, and antibodies.Screen-printed electrode structures are also frequently incorporated with mediators (e.g., Meldola blue, Prussian blue), cofactors (e.g., reduced form of nicotinamide adenine dinucleotide (NADH), pyrroloquinoline quinone (PQQ)), stabilizers, immobilization matrixes and/or additives (e.g., cellulose acetate, Naon), and cross-linkers (e.g., glutaraldehyde) to enhance the biosensor's sensitivity, selectivity, stability, and repeatability. 23he ceramic substrate-based screen-printed electrodes are durable and perfect for conducting electrochemical studies in non-aqueous electrolytes or at high temperatures. 24Using wellknown industrial printers, screen printed electrodes are created by depositing a mixture of layers onto a smooth surface.In terms of electrode design versatility, material compatibility, and customization, screen printing provides mass-producible, inexpensive, and highly achievable sensors.Conducting materials including carbon, graphene, and metals (silver, gold, platinum, etc.) are typically found in ink.Changes in the composition of screen-printed carbon inks have a signicant impact on the reactivity of electron transport and the analytical performance of SPEs. 25 In SPEs, conductive gold and silver inks are also used.The functional electrode is printed using carbon or gold inks, while the conductive track is printed using silver ink. 26For decades, a large number of researchers have been investigating new materials that can be utilized to modify the composition of printing inks.These materials fall into four basic categories: carbon-based (graphene, carbon nanotubes, carbon black), organic (chitosan and organic conducting polymers), inorganic (gold, silver), and composite modiers.The primary application of this approach is a nanoparticle-based screen-printed electrode modication.Numerous functional nanomaterials and synthetic detection elements have been successfully added to it. 27PEs are the basis of electrochemical (bio) sensors that are gaining popularity as analytical tools for food analysis because SPEs offer several benets that give these kinds of sensors the crucial qualities of the best biosensors such as simplicity of use, affordability, and mobility.28,29 Thus, the development of screenprinted technology has played a major role in the shi from heavy, conventional electrochemical cells to tiny, portable electrodes that may be used for on-site studies.30,31 The type of SPE chosen will rely on the particular application and target analyte.Obviously, researchers and scientists have to select the most appropriate type of SPE to meet their unique requirements, taking into various factors such as electrode material, size, and the chemical or biological modications needed for their experiments or measurements.

Diverse applications of SPEs in various fields
SPEs have a wide range of applications across various elds due to their versatility and affordability.The use of SPEs as transducers in electrochemical biosensors is a rapidly developing eld with great promise.Their exceptional qualities, such as their portability, low volume loading, and disposability, make them perfect for on-site detection in the environmental, clinical, and food sectors.Additionally, the wide variety of electrochemical biosensor designs is expanded by their subsequent modication using functional proteins. 32,33PEs are employed to detect and quantify environmental pollutants, heavy metals, and other substances in water, soil, and air.They contribute to environmental monitoring efforts and help assess the quality of natural resources. 34A lot of conventional air pollution analyzers are bulky, heavy, and very costly. 35Low-cost disposable sensors are utilized for monitoring soil and water contaminants, although they are not frequently used for gas sensing. 36Electroanalysis and SPEs are a great lowcost substitute for in situ environmental monitoring. 37onventional methods for monitoring pollutants and other environmental factors have low limit of detection (LODs) of about parts per billion (ppb); they are also very sensitive, specic, and repeatable.However, they do require expensive, centralized laboratories with high power consumption, sample preparation, and highly skilled experimentalists. 38In the eld of healthcare, SPEs play a crucial role in medical diagnostics.0][41][42] Development of inexpensive, compact, and user-friendly analytical instruments that deliver quantitative information quickly and easily on-site is clearly of interest.0][51][52][53] SPEs are vital for a wide range of applications, from basic research to real-world applications due to their adaptability and accessibility.

Characteristics and advantages of SPE's
The success of SPEs as transducers in electroanalytical devices make sense when one considers all of its positive qualities, chief among them being their disposability when paired with precision.Although SPEs are now widely used for food analysis and quality control, paper was demonstrated for two decades to be an innovative substrate for the development of promising analytical devices.5][56][57] The most signicant characteristic of SPE sensors are their low cost, large production capacity, and tiny microelectronic size, which enable the sample volume needed for analysis to be as small as a few microliters.9][60][61][62] Their diverse applications versatility, portability, customization and cost effectiveness made as an absolute alternative to traditional electrochemical sensors.

SPE's in food analysis
In order to reduce food waste and avoid foodborne diseases, SPE-based sensors are used as complementary analytical tools to traditional approaches in the management of food spoilage.This allows for quick screening at any stage of the food supply chain.SPEs have emerged as invaluable tools in the realm of food analysis, providing an efficient and versatile platform for assessing food quality, safety, and nutritional content.In order to assess food safety and quality, this review offers a thorough overview of SPE-based sensors.It focuses on identifying signicant contaminants in food samples, such as metal ions, toxins, pesticides, and food infectious agents.Following the discussion of food contaminants, a detailed description is given on the evaluation of food samples' antioxidant capacity, analysis of vital nutrients with the identication of food quality, and detection of food safety requirements.

Detection of food contaminants
5.1.1.Detection of toxins.Numerous electrochemical paper-based sensors have been created since they were initially introduced a decade ago in order to detect toxins in food.Food poisoning and other foodborne illnesses are frequently brought on by these pollutants.Furthermore, a number of proteins in food can cause hypersensitive reactions in some individuals.Consequently, quick food material analysis via electrochemical paper-based sensors may offer an extra degree of security to stop consumers from consuming food that is contaminated.The uses of the sensors for identifying each class of contaminants will be covered in more detail in the sections that follow.
SPEs are employed to detect toxins and quantify contaminants in food products, including heavy metals, mycotoxins, and pesticide residues.These contaminants can pose health risks, and SPEs provide a rapid and cost-effective means of analysis.In the study conducted by Jigyasa et al. 63 an electrochemical nitrite biosensor was developed using synthesised alkali metal (Na/K) doped graphitic carbon nitride (g-C 3 N 4 ).The Na-infused g-C 3 N 4 (Na-CN-300) exhibited impressive electrochemical performance for nitrite detection, exhibiting a low detection limit of 1.9 mM and a linear response in the concentration range of 10 mM to 2 mM.The sensor displayed excellent selectivity, sensitivity, and stability over 30 days, making it a helpful tool for nitrite measurement in water and food samples.The study offers a novel and facile method for synthesizing doped graphitic nitride materials and utilizing them for electrochemical sensing applications.
In another research, Orduz et al. presents a new amperometric sensor for triclosan detection utilising a screen-printed carbon nanotube electrode upgraded with Guinea grass peroxidase (GGP). 64The GGP-modied electrode demonstrated enhanced electrochemical response to triclosan compared to the bare electrode.It exhibited high sensitivity and a low detection limit of 3 mM for triclosan.The system integrates carbon nanotubes and GGP to create a potential tool for environmental analysis and food quality control.This electrochemical detection system offers promising applications for in situ analysis of environmental samples.An additional investigation into the label-free detection of Aatoxin B1 (AFB1) in food samples using an aptasensing device built magnetically.The micro electrolytic cell is a disposable screen-printed carbon electrode (SPCE) covered in a polydimethylsiloxane (PDMS) layer.The device employs thiolated aptamers immobilized on Fe 3 O 4 @Au magnetic beads, put together on the SPCE working electrode within seconds.The sensor demonstrates a wide range for AFB1 detection (20 pg mL −1 to 50 ng mL −1 ) with a low detection limit (15 pg mL −1 ).It offers a simple, economical, and highly sensitive solution for food safety quality control and has the potential to be adapted for other target molecules if specic aptamers are available. 65or the voltammetric measurement of Roxarsone (ROX) in chicken purge and river water samples, a lab-made screenprinted electrode based on poly(ethylene terephthalate) (PET) substrate modied with a hybrid lm containing gold nanoparticles-decorated graphene (AuNPs-GRA/PET-SPE) was used.In diluted river water and chicken purge samples, the technique produced a limit of detection of 60 nM and 97 nM for ROX, respectively. 66In order to detect foodborne pathogens with high sensitivity and selectivity without the need for washing, an electrochemical biosensor chip for signal amplication was created.This chip integrates methyl blue (MB) as the hybridization redox indicator and loop-mediated isothermal amplication (LAMP), which is based on in situ nucleic acid amplication.The SPE used in the electrochemical biosensor chip design was altered with gold nanoparticles (Au NPs) and encased in a polydimethylsiloxane membrane to create a microcell. 67Bacterial diseases such as listeriosis can cause meningitis, gastroenteritis, infections in pregnant women, and other symptoms.In 25-30% of cases, listeriosis is fatal. 68The tungsten sulphide (WS 2 ) nanostructure was added to a screenprinted carbon electrode (SPCE) to create the aptasensor, which was then immobilized using an aptamer.In this work, a sophisticated electrochemical biosensor for the detection of Salmonella enterica serovar typhimurium (S. typhimurium) is presented.The invention uses mercaptoacetic acid (MAA)induced self-assembled monolayers (SAM) production to immobilize anti-Salmonella antibodies on a gold (Au) electrode.Its effectiveness in articially contaminated food and water samples was in line with conventional techniques, highlighting it's reliability in real-world situations. 69.1.2.Detection of pesticides.1][72][73] Electrochemical techniques, known for their rapid response, play a vital role in pesticide detection.For example, the toxic pesticide lindane has been successfully detected using 1D graphitic carbon, such as multi-walled carbon nanotubes (MWCNTs), which signicantly enhances sensor sensitivity. 74Additionally, molecularly imprinted sensors utilizing graphitic carbon nitride and polyoxometalate nanocomposites have been developed for lindane detection, 75 showcased the versatility of electrochemical approaches in addressing pesticide contamination concerns.
This study proposed a simple electrochemical surfaceenhanced Raman spectroscopy (EC-SERS) method that only requires one "mixing and detection" to detect the neonicotinoid pesticide acetamiprid (AAP).The residues of AAP have become a major concern for fruits and vegetables.In this case, the surface of the screen-printed electrode (SPE) was altered by the application of silver nanoparticles (AgNPs).The technique is a useful tool for keeping track on pesticide residue levels in food samples. 76Based on acetylcholinesterase inhibition, an enzymatic electrochemical biosensor was developed for the indirect detection of organophosphates (OPs).Copper nanowires (CuNWs) composited with reduced graphene oxide (rGO) were added to the SPCE in order to improve the biosensor's performance.With its excellent recovery rates and lack of interference, this sensor is helpful for analysing the presence of chlorpyrifos in drinking water and orange juice. 77Using impedance electrochemistry spectroscopy, the AgNPs/carbon dots/MWCNTs nanoarchitecture, distributed over a gold-printed electrode surface, demonstrated exceptional electrocatalytic activity for fenitrothion measurement in acetate buffer at pH 4.5, with a detection limit of 0.48 nmol L −1 .The method was also used to identify fenitrothion pesticide, and other pesticides in orange juices. 78 highly sensitive electrochemical aptasensor against chlorpyrifos (CPF) was developed using novel carbon quantum dotsgraphite composite ink-based screen-printed electrodes (CQDs/ SPEs).With increasing volumes, the produced aptasensor responded well to potato extract that had not been spiked.As a result, the created aptasensor showed a respectable level of application in real agricultural and food samples. 79The combination of printed electronics and harmless biopolymeric lms produces plant-wearable sensors for decentralized pesticide analysis in precision farming and food safety.This article describes a straightforward process for creating exible, sustainable sensors that can detect carbendazim and paraquat in food, water, and agricultural samples.The sensors are printed on cellulose acetate (CA) substrates.The analytical performance was evaluated using square wave voltammetry (SWV) and differential pulse voltammetry (DPV) in a linear concentration range of 0.1 to 1.0 mM, with detection limits of 19.8 nM for paraquat and 54.9 nM for carbendazim, respectively.Without being restricted by other pesticides, the versatile and environmentally friendly non-enzymatic plant-wearable sensor can identify carbendazim and paraquat on tomato and lettuce skins as well as in water samples. 80.1.3.Detection of metal ions.Heavy metal ions, which persist in the environment and can lead to adverse effects on human health and ecosystems, require effective removal for protection. 81,82Some heavy metals are essential in low quantities but harmful at excessive levels, even leading to cancer or mortality. 83,84Electrochemical sensors are key in addressing heavy metal pollution, and modifying electrodes with graphenebased materials signicantly enhances their performance.Studies have shown that graphene and its derivatives, when integrated with other materials like bismuth nanoparticles or metal-organic frameworks, greatly enhance sensitivity, selectivity, and detection limits for various heavy metal ions, making them invaluable in environmental and health protection efforts. 85he study introduced an electronic tongue (e-tongue) system based on cyclic voltammetry with three different electrodes (pencil graphite, screen printed, and glassy carbon) to detect and analyze heavy metals (cadmium, lead, tin, and nickel) in sunower edible oil at varying concentrations.The cyclic voltammetry results demonstrated that each electrode (PG, SP, and GC) exhibited different sensitivity levels, with SP showing the highest sensitivity to heavy metals in the oil.Principal component analysis (PCA) was employed for classication, and the results indicated that all three electrodes effectively detected the heavy metals.The variance analysis attributed 98% to SP, 88% to GC, and 84% to PG.The e-tongue system, combined with chemometric analysis, successfully identied cadmium, lead, tin, and nickel at various concentrations in sunower edible oil, making it a valuable tool for heavy metal detection in food products. 86uang et al. reported a disposable sensor that uses square wave anodize stripping voltammetry (SWASV) to detect Pb(II) and Cd(II) ions simultaneously.Conjugated mesoporous polymer (CMP) was put onto screen-printed carbon electrodes (SPCE) aer bismuth nanoparticles (BiNPs) were electrodeposited therein.This resulted in the CMP/BiNPs/SPCE mixture.The simultaneous measurement of Pb(II) and Cd(II) in seafood samples effectively established the usefulness of the technique. 87In this study, Jian, et al. and his team reported a disposable sensor for measuring lead in genuine tap water, juice, preserved eggs, and tea samples by electrochemically depositing reduced graphene oxide (rGO) on the surface of SPCE. 88The results based on rGO-SPCE were reliable and precise when compared to results from graphite furnace atomic absorption spectroscopy (GFAAS), indicating that the disposable sensor has a lot of potential in applications for quick, sensitive, and affordable Pb 2+ detection in food.
An ion selective membrane containing zinc(II) phthalocyanine as the ionophore, together with carbon black nanomaterial, were added to the screen-printed electrodes.Recovery values ranging from 90% to 100.5% were observed when apple juice, skim milk, soybean, and coconut water samples were simultaneously tested for Fe 3+ and K + ions using the newly developed Fe 3+ -selective electrode and K + -selective electrode. 89A fresh, low-cost disposable porous graphene electrode (P-GE) enhanced with bismuth nanoneedles (nano-BiNDs) is suggested as a "mercury-free" sensor for electrochemical sensing using a smartphone to identify heavy metals.In order to create the P-GE, screen printing was used.On the P-GE, nano-BiNDs were produced using potentiostatic electrodeposition.Pb 2+ and Cd 2+ in commercial seaweed products were accurately quantied by the suggested portable sensor, and the results were in line with those of the conventional ICP-OES method. 90or the identication of heavy metals, anodic stripping voltammetry (ASV) in conjunction with a screen-printed electrode shows great promise.Using a bismuth/crown ether/Naon lm-modied SPCE, Keawkim et al. used sequential injection/anodic stripping voltammetry to measure the lead content in rice. 91ith a detection limit of 0.11 mg L −1 (110 ppb), they discovered a linear detection range for Pb 2+ of 0.5 to 60 mg L −1 (0.5-60 ppm).

Foodborne pathogen detection
Modied SPEs are employed to nd the presence of foodborne pathogens such as Salmonella, E. coli, and Listeria.They can be functionalized with antibodies or DNA probes to selectively capture and quantify specic microorganisms, contributing to food safety.The research done by Bagheryan et al., describes the development of a label-free impedimetric biosensor for the detection of S. typhimurium by contrasting two distinct aptasensor fabrication methods. 92Electrochemical graing was found to yield a denser aptamer biorecognition layer, resulting in higher sensitivity, particularly at both low and high S. typhimurium concentrations.The aptasensor displayed a linear reaction throughout a large concentration range and exhibited high selectivity for S. typhimurium.Importantly, the sensor worked effectively in undiluted real samples, emphasizing its practical applicability.The study's comparison with existing aptasensors highlights its competitive limits of detection and extended dynamic range, making it a useful addition to the eld of food analysis and microorganism identication.
Incorporating an innovative approach to DNA detection, the study made by Tsaloglou et al. showcases a cost-effective and portable electrochemical methodology designed for remotesensing applications, in particular resource-limited settings. 19y joining recombinase polymerase amplication (RPA) with an electroactive mediator, this portable instrument uses paperbased, throwaway strips with carbon electrodes screen-printed on them.It exhibits precise temperature control, allowing for diverse electrochemical detection methods, and has demonstrated proof-of-concept in screening for diseases, such as tuberculosis, as well as potential applications in monitoring food and water quality.The current sensitivity compares favourably with bench top equipment.This approach holds promise for a wide range of molecular diagnostics, paving the way for accessible, on-site DNA detection beyond laboratory settings.
Wang et al. presented a microfabricated electrochemical biosensor intended for the detection of E. coli DNA. 93This biosensor combines the high specicity of DNA hybridization with the benets of electrochemical transducers, including portability and affordability, by employing an electrochemical hybridization indicator and screen-printed electrodes.The biosensor's calibration experiments demonstrated a linear response and quantitation capability, with a detection limit of 50 ng mL −1 for E. coli DNA target.Given its low detection limit, it holds great potential for use in food testing and environmental monitoring.The development of highly specic and sensitive colorimetric and electrochemical DNA biosensors for the quick identication and quantication of Escherichia coli in seawater is a signicant contribution to the environmental monitoring and water quality assessment.
The biosensors developed by Paniel and Baudart showed a high degree of specicity against E. coli, successfully discriminating it from other microorganisms. 94With the capacity to detect 2 to 20 CFU/100 mL of E. coli in seawater, these sensors have potential for in-the-eld food and environmental 95 monitoring and also providing reliable, rapid, and cost-effective results.The study by Flauzino et al., 95 presents a label-free impedimetric genosensor that may be used to detect traces of pig meat adulteration.This device is crucial in areas where beef is prohibited from containing pork because of allergies, cultural or religious beliefs.The sensor utilizes graphene acid to enhance electrode charge transport properties, enabling the rapid detection of pork residues in beef samples within 45 minutes.This development holds signicant promise for creating sensitive and selective point-of-need sensing devices for meat purity monitoring.Incorporating these advancements in screen-printed electrode-based biosensors has proven to be a pivotal step in enhancing food analysis and quality monitoring.The representation of steps involved in food pathogen detection are shown below in Fig. 2.
In this study, screen-printed electrodes (SPEs) were functionalized via a facile strategy with surface imprinted polymers (SIPs).The SIP-coated SPEs were used in combination with the heat transfer method (HTM) for the real-time detection of Escherichia coli.The sensor was tested in buffer, with a reproducible and sensitive response that attained a limit of detection of 180 CFU mL −1 .Furthermore, selectivity was assessed by analysing the sensor's response to C. sakazakii, K. pneumoniae and S. aureus as analogue strains.Finally, the device was successfully used for the detection of E. coli in spiked milk as proof-of-application, requiring no additional sample preparation. 96ng et al. suggested a polymer sensor based on screenprinted electrodes for the particular detection of Salmonella typhimurium. 97In order to establish distinct binding cavities, the sensor was built by electropolymerizing dopamine while Salmonella typhimurium was present on the electrode surface.With a detection limit of roughly 101 CFU mL −1 and a detection time of only 4 min, the sensor showed excellent specicity for Salmonella typhimurium.It was also able to distinguish Salmonella typhimurium from other common foodborne pathogens like Escherichia coli and Listeria monocytogenes.Real food samples, such as milk and pork, were used to test the sensor's performance, demonstrating that it is a good t for the quick and on-site identication of harmful bacteria.
Wang et al. reported a detailed review describing the important research progress of DNA-based electrochemical biosensors for the detection of foodborne pathogenic bacteria through four perspectives: representative foodborne pathogens detection using electrochemical approaches, DNA immobilization strategies of aptamers, DNA-based signal amplication strategies used in electrochemical DNA sensors, and functional DNA used in electrochemical DNA sensors. 98Finally, perspectives and challenges are presented in this eld.This review will contribute to DNA-based electrochemical biosensor in enhancing the nucleic acid signal amplication.All of these investigations together highlight the possibility of on-site, sensitive, and quick detection techniques that greatly aid in guaranteeing food safety.

Antioxidant capacity assessment
SPEs are used to assess the antioxidant capacity of food samples, such as fruits, vegetables, and beverages.This is crucial for evaluating the potential health benets and quality of these products.A study on the effects of electrochemical oxidation processes during voltammetric analysis of wine samples, which can obstruct the surface of screen-printed carbon electrodes (SPCE) and result in lower total polyphenols content compared to glassy carbon electrodes.The research explores treatments to remove this fouling layer, highlighting the potential for SPCE reuse in wine analysis, particularly for quality control. 99nother research introduces a novel electroanalytical nanostructured sensor for quantifying vitamin C in commercial infant foods.This sensor, SPCEs modied with Au nanoparticles and reduced graphene oxide akes, offers a low LOD of 0.088 mg L −1 , making it suitable for quality control labs.Its fast response, ease of use, and disposability make it a valuable tool for assessing vitamin C content in complex food matrices and potentially other compounds relevant in food chemistry. 100sing a disposable screen-printed graphene electrode, a straightforward and sensitive electrochemical sensor is displayed for calculating the total vitamin K (K1 and K2) in green vegetables.The study explores parameters affecting sensitivity and demonstrates the sensor's application for quality control of vitamin K1 in natural samples.The method's economic and environmentally friendly nature, as well as its potential for determining other compounds, suggests its utility in food quality analysis and the creation of food composition tables. 101here is another research which explores the electrochemical detection of the important antioxidant compound, gallic acid (GA), found in various food and beverage sources.Two detection methods using different devices were employed and validated with actual samples like wine, green tea, apple juice, and serum enhanced with GA.These methods demonstrated specic calibration curves, low detection limits, rapid response times, and excellent sensitivity, which qualies them for wider uses in determining the antioxidant levels of food, environmental, or clinical samples reported in GA equivalents. 102aribas et al. presented a method for measuring gallic acid (GA) at the nanomolar level using modied kaolinite minerals (KNT) and gold nanoparticles (AuNps) on a screen-printed electrode (SPE). 103The suggested method's applicability was conrmed through the quantitative analysis of GA in samples of pomegranate juice and black tea.Chakkarapani et al. 104 utilises modied reduced graphene oxide and silver nanoparticles (RGO-Ag NPs) based SPEs to selectively and sensitively determine phenolic substances, such as butylated hydroxyanisole (BHA) and vanillin (VA), which are well-known phenolic compounds frequently utilized as preservatives in various foods and beverages.An electrochemically activated screen-printed boron-doped diamond electrode (aSPBDDE) was developed by Kozak et al. for the measurement of the polyphenolic antioxidant curcumin (CCM). 105Th prepared sensor was a highly simple, rapid, and sensitive when tested by differential pulse adsorptive stripping voltammetry (DPAdSV) method.The electrode has shown to be a very useful instrument for precisely and accurately determining CCM in food samples directly.A portable technology prototype was created by Ivanova, et al. 106 to measure antioxidant capacity (AOC) potentiometrically.An electrochemical microcell with two identical electrodes with isolated spaces functions as the device's functional unit.The working and reference electrodes were two identical printed electrodes (CSPEs).In a few years, it might be readily modied to serve as a single-use tool for on-site analysis.

Nutritional analysis
SPEs are employed to measure the concentration of essential nutrients in food products.They can be used to assess vitamins, minerals, and amino acids in different food matrices.An electrocatalytic screen-printed sensor was developed to measure vitamin B1 (thiamine) in food supplements.The sensor, utilizing a cobalt phthalocyanine mediator, allowed the electrochemical conversion of vitamin B1 to an electrochemically active thiolate anion under basic conditions.As a result, selectivity was increased and the detection limit was lowered, resulting in a better analytical response current at an operating potential of 0 V vs. Ag/AgCl.The sensor exhibited a linear response within the 0.1 to 20 mg mL −1 range, so rendering it appropriate for measuring vitamin B1 in commercial products.The sensor's performance was validated by achieving mean recoveries of 101% for a multivitamin tablet and 93.3% for a multivitamin beverage, suggesting that it may be used to ensure the quality of food supplements and other goods. 107inoacids: for the purpose of detecting biogenic amines (BAs), which are essential to the safety and quality of food, such as histamine, putrescine, and cadaverine, electrochemical biosensors were created.To construct mono-enzymatic and bienzymatic biosensors, these sensors used diamine oxidase (DAO) coupled to magnetic beads (MBs) that were immobilised on different electrodes.Signicantly, these biosensors showed outstanding stability over an extended period of time, indicating their suitability for long-term application.They were successfully used to identify BAs in naturally deteriorated and spiked sh, demonstrating their usefulness for quantitative investigation. 108 silver/carbon screen-printed electrode (S/C-SPE) was fabricated using polymer-based conductive inks blended with in-house synthesized nanoparticles and investigated for its application in electrochemical analysis.Silver nanoparticles (∼59 nm) and carbon nanoparticles (∼76 nm) were synthesized having zeta potential of <±60 mV and particle morphology were investigated for both the nanoparticles.These nanoparticles were blended with a thermoset epoxy resin to formulate different conductive inks viz.silver (Ag) ink, carbon (C) ink and silver/silver chloride (Ag/AgCl) ink.The electrode was applied to determine the level of vitamin C in different fruit juices at the S/ C-SPE using a developed voltammetric method and compared with that of standard biochemical method. 109Westmacott et al. described the development of a novel electrochemical assay for the measurement of water-soluble vitamins in food and pharmaceutical products. 110The optimum conditions for the determination of vitamin B 1 (thiamine), B 2 (riboavin) and B 6 (pyridoxine) in phosphate buffer were established using cyclic voltammetry in conjunction with screen printed carbon electrodes (SPCEs).The method was also applied to a multi-vitamin supplement for the simultaneous determination of thiamine, riboavin and pyridoxine.
A novel electrochemical sensor was proposed for the simultaneous determination of fat-soluble vitamins (A, D, E, K) using a screen-printed graphene/Naon electrode (SPGNE).The scanning electron microscopy was used for morphological characterization of the electrode surface.The electrochemical behaviors of fat-soluble vitamins have been studied in a mixture of ethanol and sodium perchlorate monohydrate using squarewave voltammetry (SWV).These developed sensors provided high sensitivity in detection and offer high potential to apply them for the simultaneous determination of fat-soluble vitamins in dietary supplements. 111The purpose of this study was to develop an electrochemical sensor for detection of amaranth.The electrochemical sensor based on the modication of a screen-printed electrode via polypyrrole nanotubes (PPy NTs/ SPE) for detection of amaranth was developed.The preparation of PPy NTs was performed through the pyrrole monomer oxidation with iron(III) chloride in exposure to methyl orange as structure-guiding agent.Findings exhibited an excellent electrocatalytic activity of as-fabricated sensor for amaranth detection.Moreover, the proposed sensor could practically and successfully determine the amaranth content present in the real food specimens, with acceptable recovery rates. 112

Food quality detection
Utilising a recently created biosensor that is built on a screenprinted electrode modied with tyrosinase and single-layer carbon nanotubes (SPE-SWCNT-Ty), hydroxytyrosol (HT) levels in commercial extra virgin olive oils (EVOO) of different kinds and origins were measured.Tyrosinase was rendered to immobile on a screen-printed electrode made of carbon that had been altered to include single-layer carbon nanotubes (SPE-SWCNT-Ty).The results of the study validated the high quality of commercial EVOOs by showing that they contain notable levels of HT.SPE-SWCNT-Ty is a biosensor that shows potential for regular food quality monitoring, especially when evaluating vegetable oils 113.Duan et al., focused on the rapid detection of sucralose and trichloroacetic acid (TCA), which are halogenated organic compounds, in water bodies. 114The Ag/C material is derived from bread waste, contributing to a sustainable circular economy by repurposing food leovers.The electrochemical process's performance was initially assessed using free chloride ions, followed by the analysis of the target analytes.In response to the increased need for authenticity and quality monitoring, the study offers a technique for differentiating between premium and regular American lager beers.The method uses screen-printed electrodes (SPEs) that are commercially available.These include carbon (SPCE), gold (SPGE), and carbon nanotube (SPEs-CNT) electrodes.The SPEs are combined with chemometric classication techniques like partial least squares regression discriminant analysis (PLS-DA) and so independent modelling of class analogy (SIMCA).In the validation dataset, the PLS-DA models yielded average scores of 88% for sensitivity, specicity, and precision, whereas the SIMCA models demonstrated average scores of 72%, 82% for specicity, and 80% for precision.Using SPCE in conjunction with PLS-DA, the nal setup showed a 94% predictive power, and a single SPCE could analyse up to 35 beers every SPE. 115In addition to food quality detection, the presence of heavy metals, toxic elements and food allergens in food materials shows the advantageous aspect of SPE in multidimensional concept and elaborated in Fig. 3 for further discussion.
Investigation done by Cinti et al., proposed a paper-based screen-printed biosensor designed for the purpose of detecting ethanol levels in beer samples. 116To detect ethanol, a nanocomposite consisting of Carbon Black (CB) and Prussian blue nanoparticles (PBNPs) was employed as an electrocatalyst.This nanocomposite was utilized to measure hydrogen peroxide generated during the enzymatic reaction between alcohol oxidase (AOx) and ethanol.Following parameter optimization, the biosensor demonstrated the capability to quantify ethanol in various beer types effectively.A single-use screen-printed carbon electrode strip was developed, featuring a surface modication with Pt-MWCNT nanohybrids, for detection of hydrogen peroxide (H 2 O 2 ).This sensor strip could effectively measure H 2 O 2 levels in green tea infusion and pressed tofu, yielding results comparable to those obtained through the ferrous oxidation xylenol orange (FOX) assay and the peroxidase colorimetric method. 117In another study, a highly sensitive electrochemical sensor was developed for the precise detection of the cytotoxic food preservative tert-butylhydroquinone (TBHQ) at nanomolar levels in edible oils and water samples which has signicant importance in maintaining food quality.The sensor utilized a novel nanocomposite consisting of cupric

Review
RSC Advances oxide (CuO) decorated amine-functionalized carbon nanotubes (NH 2 -CNTs). 118t achieved an ultra-low detection limit of 3 nM and remarkable sensitivity at 37.7 mA mM −1 cm −2 .The device demonstrated exceptional resistance to interference, stability, reproducibility, and repeatability.Real sample analysis further validated the sensor's practical feasibility, yielding exceptional recovery rates in the range of 95.90% to 104.87% and a maximum relative standard deviation (RSD) of just 2.71%. 119

Food safety standards detection
The rapid expansion of the food industry, coupled with the rising need for prolonged shelf life and food conservation, necessitates effective techniques for conveniently monitoring the safety and freshness of food products.This is of paramount signicance to consumers, serving to safeguard both their health and nances, and to reduce unnecessary food wastage.The deterioration of food freshness, as observed in items like meat, sh, or poultry, can be discerned through key spoilage indicators originating from the degradation of lipids, proteins, and adenosine triphosphate (ATP). 120anthine oxidase from Bacillus pumilus RL-2d was covalently immobilised onto screen-printed multi-walled carbon nanotubes gold nanoparticle-based electrodes (nano-Au/cMWCNT) to construct an amperometric biosensor for xanthine.With a limit of detection (LOD) of 1.14 nM, the sensor showed a sensitivity of 2388.88 mA cm −2 nM −1 .It was used to evaluate the sh meat's freshness. 121 three-dimensional self-supported electrocatalyst was developed by Malhotra et al., incorporating cerium oxide nanocrystals doped with cobalt (CeO 2 -Co) onto tin oxide (SnO 2 ) nanorods on a carbon cloth substrate. 122This binder-free sensor exhibited excellent sensitivity (3.56 mA mM −1 ), a large linear range (25 nM to 55 mM), and a less detection limit (58 nM) for xanthine (XA) detection.The material was employed in a screenprinted electrode for accurate XA detection in food samples, making it a promising tool for food-safety standards monitoring.This study presents the development of a screen-printed disposable paper device integrated with buckypaper for the detection of phthalates.The device offered a linear detection range from 70 ppm to 15 ppm, with a low detection limit of 12.64 ppm.It demonstrates potential for point-of-care testing in assessing phthalate levels in food safety and quality. 123n extensive research carried out by Pennazza et al. introduces an innovative voltammetric sensor that interacts with gas and vapor through a screen-printed electrode system immersed in a liquid solution. 124The sensor demonstrates acceptable reproducibility and sensitivity in calibration tests with carbon dioxide (CO 2 ) and oxygen (O 2 ).Additionally, the study showcases its potential for various applications in air quality monitoring, food packaging control, biochemical studies, and biomedical research.Studies presents a straightforward synthesis of gold nanoparticles (AuNPs) decked ultrathin graphitic carbon nitride nanosheets (g-C 3 N 4 ) composite using ultrasonication.The resulting g-C 3 N 4 /AuNPs composite is employed to create a highly efficient electrochemical sensor on a screen-printed carbon electrode (SPE) for the sensitive detection of cafeic acid (CA) in numerous food samples.The sensor exhibits rapid response and excellent sensitivity, for regular food quality control and analysis. 125This study presents a new electrochemical method using a cobalt phthalocyanine-modied screen-printed carbon electrode (SPCE/CoPc) to investigate myoglobin's scavenging activity against Fig. 4 Integration of SPEs with artificial intelligence (AI) for various applications.
peroxynitrite (PON) in meat extracts.It is a valuable tool for studying the kinetics of oxidative processes involving PON in physiological conditions and assessing the freshness. 126PEs are versatile tools that facilitate precise and costeffective electrochemical measurements, making them indispensable for food analysis in research, quality control, and compliance with food safety regulations.

Future directions
Certainly, here are some potential future directions and areas of research and development in the eld of screen-printed electrodes (SPEs) in the context of food analysis.Integration of SPEs with AI helps to make predictions on classication, visualization of quality and accuracy of results and its versatile applications is schematically represented in Fig. 4.

Miniaturization and portability
One of the future directions for SPEs is the continued miniaturization and development of portable devices.Researchers can work on creating more compact and user-friendly SPE systems, enabling eld testing and on-site analysis.These advancements could have a signicant impact on food safety inspections, allowing for real-time monitoring and rapid decision-making. 26

Application in wireless sensor and integration with artificial intelligence
Many facets of screen-printed electrode recognition need to be explored in order to progress this sector.A lot of wireless sensor applications involve installing or attaching sensors to the body's surface.Therefore, more investigation is required into the interference and dependability of signals generated by wireless technologies in biological systems.Therefore, extensive clinical trial investigations and coordination and collaboration with medical professionals are necessary for the complete validation of clinical studies.It will assist in elucidating the currently ambiguous link between analytical concentrations and clinical acceptability.Though there is still much to learn about the electronic screen, the full potential of SPEs remains unexplored.][129][130] In the food business, AI presents an opportunity.Precision farming and numerous other uses in food production and consumption make it indispensable to the upkeep of our food chain.In the food industry, it can also be applied as a quality control method.AI is revolutionizing the way people think about food production, quality, distribution, etc., and the rise of intelligent mobile apps has played a signicant role in this shi.Food databases can be efficiently created and analyzed by arti-cial intelligence.Both customers and employees may benet from a healthier and more reasonably priced food business as a result.The techniques employed by industry to identify food adulteration are highly costly.Megalingam et al. 131 present a novel approach to food deterioration detection by fusing articial intelligence, machine learning, and photo categorization (20).In order to identify food that is decaying, they have used AI, deep CNN networks, computer vision, and machine learning techniques like the k clusters approach for color clas-sications in photos and its HSV values for spoiling detection.This project is completed on the Jupyter notebook platform using the anaconda prompt.Additionally, Iwendi et al. 132 used a network classier and articial intelligence to detect and analyze security levels on the internet of things.The study demonstrates a very high accuracy rate for the suggested use.According to this perspective, AI is benecial in practically every industry today.

Wireless connectivity
Almalki uutilises drones equipped with Radio Frequency Iden-tication (RFID) sensors to monitor food safety and quality.For safety and security reasons, the proposed model design seeks to wirelessly test the resonance frequency of items dielectric constants from an airborne drone.This work bridges a knowledge gap and presents a novel approach to the Internet of Everything (IoE) in food safety through the use of drones in production, logistics tracking, warehouse management, and product authenticity assessments.Utilizing MATLAB soware and simulation results from CST microwave studio, it is conrmed that using drones and RFID to determine the safety and quality of food is a potential and a non-expensive approach. 133A simple diagrammatic representation of integration of SPEs with wireless connectivity is represented in Fig. 5.

In situ monitoring
Research can focus on the development of SPEs that can be embedded directly in food packaging or storage containers.These sensors would continuously monitor food quality and safety, providing consumers with real-time information on product freshness. 134

Blockchain and traceability
Combining SPEs with blockchain technology can enhance food traceability and transparency.Each food product could have Review RSC Advances a unique identier linked to a blockchain, and SPEs could be used to verify the authenticity and safety of the product at various points in the supply chain. 135

Personalized nutrition
The development of SPEs that can provide real-time nutritional information based on individual dietary needs and preferences is an exciting future prospect.These sensors could help consumers make more informed choices and promote personalized nutrition. 136hese future directions hold great promise for the continued advancement of SPE technology in the eld of food analysis, contributing to improved food safety, quality, and sustainability.Researchers and industry professionals working together can drive innovation and bring these ideas to fruition, beneting both the food industry and consumers.

Advantages and limitations of SPEs
SPEs are advantageous over other methods of electrode production because they allow for simple control over the electrode's composition, thickness, and surface area.Additionally, catalysts can be easily combined with printing ink.Additionally, they provide the opportunity for experimental statistical conrmation of the outcomes even in the case of duplicate electrodes.The fact that they can only be used on atbeds is their most obvious drawback. 137SPEs eliminate the need for pre-treatment or electrode storage and enable the completion of several tests using small amounts of materials and reagents.These electrodes are frequently used for analysis in the food sector, environment, medicine, pharmacy, and agriculture. 138SPEs can be generated on demand for analysis, despite the fact that their shapes are known to vary.Additionally, they are available in many shapes as a band, ring, or disc.SPEs are utilised to analyse multiple unknown samples quickly and concurrently in addition to doing calibration.Notwithstanding the aforementioned benets linked to SPEs, their incompatibility with nonplanar substrates persists as a drawback, hence restricting the fabrication process.Therefore, further work needs to be done on SPEs, which are printed directly onto a variety of exible and inexible substrates. 139

Conclusion
Screen-printed electrodes (SPEs) have revolutionized the arena of electrochemistry and have become indispensable tool for an extensive range of applications, counting but not limited to environmental monitoring, clinical diagnostics, food analysis, and quality control.SPEs come in various types, each tailored to specic applications, making them versatile and adaptable to diverse research and industrial needs.Their cost-effectiveness and ease of mass production have democratized electrochemical analysis, making it accessible to researchers and professionals.
In the context of food analysis, SPEs have emerged as critical instruments in ensuring the quality, safety, and nutritional content of food products.They play a vital role in detecting contaminants such as toxins, pesticides, and heavy metal ions, providing rapid and cost-effective solutions for food safety assessments.Moreover, SPEs are utilized in the detection of foodborne pathogens, allowing for selective and sensitive quantication of microorganisms that can jeopardize food safety.These sensors nd applications not only in laboratories but also in on-site and point-of-care testing, making them crucial in addressing food safety concerns.
SPEs are also instrumental in assessing the antioxidant capacity of food samples, aiding in the evaluation of potential health benets and quality.They enable the quantication of essential nutrients, vitamins, minerals, amino acids, and other compounds in food matrices, contributing to nutritional analysis and quality control.Additionally, SPEs are used for detecting and distinguishing between various food and beverage products, offering an effective means of food quality detection, thus enhancing consumer condence and reducing food waste.
Furthermore, as the food industry continues to expand, ensuring food safety and quality is of paramount importance.SPEs are playing an ever-increasing role in the monitoring of food products' safety and freshness.By detecting spoilage indicators arising from the degradation of lipids, proteins, and ATP, they contribute to maintaining the integrity of food products, thereby safeguarding consumers' well-being.
The application of screen-printed electrodes in food analysis has signicantly advanced the eld, offering precise, efficient, and cost-effective solutions for various food-related challenges.Their versatility, adaptability, and accessibility make SPEs an invaluable resource, enhancing the quality and safety of food products, thereby beneting both consumers and the food industry.As research and technology continue to evolve, the role of SPEs in food analysis is poised to expand, further contributing to the improvement of food quality and safety standards.

Dr
Ashok K. Sundramoorthy is Professor of Material Science, Dept. of Prosthodontics, Saveetha Dental College and Hospitals.He received his PhD from National Taipei University of Technology (NTUT) (2005-2009), Taiwan.He worked as a Res.Asst.Professor at Dept. of Chemistry, SRM University (2016-2021).He did postdoctoral fellowships at the University of Wisconsin-Madison, United States (2013-2016), Nanyang Technological University, Singapore (2010-2013) and NTUT, Taiwan

Fig. 2
Fig.2Representation of steps involved in food pathogen detection.

Fig. 3
Fig.3Representation of list of food contaminants detected by SPE.

Fig. 5
Fig. 5 Integration of SPEs with wireless connectivity.